Tool for securing inserts in tapped holes



Dec. 11, 1945. H. w. CRAM ErAL I TOOL FOR SECURING INSERTS IN TAPPEDHOLES 2 Sheets-Sheet 1 Filed June 3, 1944 INVENTORS. HARKNESS m CRAM BYERW/N E ENER [4 651 I: M

HTTOR/Vfl) D H. w. CRAM EIAL T0011 FOR SECURING INSERTS IN TAPPED HOLES2- Sheets-Sheet 2 Filed June 5, 1944 All w R I I INVENTORS.

M w ME W m/ W WM SE. 5 NWf KW RR/ ML wy N .8 nut Patented Dec. 11, 1945OFFICE .v.

TOOL FOR SECURING INSERTS IN TAPPED HOLES Harkness W. Cram, MountVernon, and Erwin Eckener, Bronx, N. Y., assignors to Aircraft ScrewProducts Company, Inc., Long Island City, N. Y., a corporation of NewYork Application June 3, .1944, Serial No. 538,590

9 claims.

The invention relates to a tool for securing the end of a wire coil in atapped hole or a boss or nut member into which the coil is inserted asan interiorly threaded lining. The invention contemplates the provisionoi. a tool whereby the coil end preferably shaped for this purpose witha sharp edge or serration of its outer periphery can be forced into thematerial of the tapped thread groove in which the coil end is located. Acoil end thus embedded will be prevented from being backed out of thetapped hole when a stud engaging the coil is turned loose. A furtherobject of the invention is the provision of a tool whereby the coil endcan be secured in the boss member and-simultaneously widened in order tofacilitate the grip of the first convolution of a stud which is to bescrewed into the wire coil threading. The invention also aims to combinea tool for the indicated purpose with a staking punch to drive orcompress, from the outside, the material of the 'boss or nut member inthe range of the embedded coil end and also in the rear thereof.

The invention mainly consists of a tool comprising a tubular memberexternall threaded in part, according to the internal threadingconstituted by a coil for which it is destined, and so slitted as toform a longitudinally extending tongue, provided with a portion of onethread to engage from the inside the coil end to be secured in the boss.,The tool also comprises means to spread said tongue outward. The toolaccording to the invention may be combined with a punch having a frontface teethed in an arc substantially corresponding to the width of thetongue,

the punch being so guided that the teethedportion is in registry withthe tongue.

Further objects and details of the invention will be apparent from thedescription given hereinafter and the accompanying drawings illustratingembodiments thereof byway of example.

In the drawings,

Figs. 1 and 2 are side and front elevations respectively of a portion ofa wire coil insert of a form to which the tool can be applied withparticular advantage; I

Fig. 3 is a side elevation of an embodiment of the tool according to theinvention;

Fig. 4 is a longitudinal cross-section thereof; Fig. 5 is across-section along line 5-5 of Fig. 4;

Fig. 6 is a side elevation of a portion of the tool on a larger scale;

Fig. 6a is a side elevation of a modified portion of the tool;

Fig. 7 is a side elevation of another modification; 7

Fig. 8 is a longitudinal cross-section of another embodiment; and

Fig. 91s a cross-section along line 9-9 of Fig. 8.

The principle of the invention is applicable to wire coil inserts of anydesired cross-section. Hence, the diamond shape shown in Figs. 1 and 2is selected as an example illustrating one of a variety of conventionalforms. However, in order to attain best results by the application ofthe tool according to the invention, it is advisable to provide an endportion of the coil to be secured in the tapped hole of a boss or-nutmember with a sharp outer edge, if such is not already by itself part ofthe cross-section of coil wire. It is also advantageous to serrate thecoil end portion in order to provide for a plurality of teeth which maybe forced into the material of the boss or nut member after theinsertion of the coil. Figs. 1 and 2 show such a coil I with an endportion 2 which comprisesapproximately a quarter convolution and isprovided with recesses 3 of the outer edge 4, thereby forming aplurality of teeth 5. I

The tool of Figs. 3 to 6, for securing a coil of that type, comprises atubular body 6 of an outer diameter corresponding to the inner diameterof the coil insert to which the tool is to be applied.

The body 6 is provided with two longitudinal slits I spaced from eachother approximately a quarter of the circumference of the body 6. Theslits start at points 8 at a short distance from the one end of the body6, and extend to points 9 where they are connected by a transverse slitIII. The length of the slits 1 is so selected that a. fairly wellresilient tongue is formed by the slits. The remaining three-quartercircumference portion of body 6 is provided with an external threading[2 of a length, pitch and diameter according to the internal threadingconstituted by a coil for which the. tool is destined, and which may beof a shape as shown in Figs. 1 and 2. The threading I2 is so locatedwith respect to points 8 and 9 that the tongue portion in registry withthe threading l2 can be deflected a sufficient distance by a forceacting from the interior of the body in a manner and for a purposedescribed hereinafter. The tongue is provided with a portion iii of onethread only which is located in continuation of that end of thethreading l2 which is nearest to the transverse slit ll! of the tongue.Now it will be clear that the body 6 can be screwed, starting from theend 2, into a coil I til the end portion 2 is located in the threadportion I3 provided on tongue II. In order to prevent further insertionof the tool into the coil, the thread I3 may end at an abutment on thatside of the tongue where the ultimate end of the combined threading I2and I3 is'located. Such abutment may be provided either as the abutmentIt on the tongue proper (Fig. 6) or on the remainder portion of the body8 close to the threading I2 as the abutment Ill in registry with thetongue thread H3 in Fig. 6a. The diameter of the inner cylinder portionI! of the tubular member 6 from which the major portion of the tongue IIis formed is smaller than the inner cylinder it of the other end portionII of the body which may be of a somewhat larger outer diameter than thebody portion I3 in the range of the tongue I I. The inner cylindricalportions I5 and I6 are'connected by a conical portion I8. Interiorly ofbody 8 a rod-like driver I 9 is movable in axial direction. One end ofthe driver I9 has an inner end portion fitting the cylinder portion I5of member 8. A portion 2i remote from the end 26 is also cylindrical,having a diameter according to that of the inner cylindrical bodyportion I6. Intermediate the portions 20 and 2| there is a portion 23,having an inclined face 24 shaped according to the conical portion I3 ofbody 6.

The cross-section of the portion 23 is such that the driver I9 can bepushed inward, i. e. to the left in Fig. 4, thereby to bear as a wedgeagainst the inner side 25 of the tongue II, in order to force the tongueoutside. The end 26 of the driver I9 opposite its aforementioned end 20is screw-threaded to receive thereon a nut 21 and a stop collar 28secured to the driver is by a rivet 28 or the like. The rod has also anextension 3!] beyond the portion 26. The extension 30 constitutes a headto which the pressure, for instance by a hammer, may be applied in orderto push the driver I9 inward against the restraint of the tongue I I. Aguide pin 3I is secured to the driver is intermediate its ends so as toengage a longitudinal slot or groove 32 provided for this purpose in thewall of the body 8. This arrangement insures that 'the driver face 24moves in registry with the tongue I I.

In order to apply the tool to an insert lining of a tapped hole of aboss member, first body 6 is 1 screwed into the insert from the side ofthe insert portion 2 (Fig. 2) until that end portion abuts against thestop It provided on the tongue II. This can be readily done because thetongue without any restraint from the inside will be in truecontinuation of the circumference of the body 8. In this position of thebody, the driver I9 is inserted with the guide pin 3I in slot 32 andpushed or hammered inward a. desired distance. This distance can beadjusted by the setting of the nut 21 which finallyc'omes to bear on theend surface 33 of the body 6. The driver by moving inward wedges outwardthe tongue II which is in engagement with the coil end 2 located in thethread portion I 3. Thereby the coil end 2 will be firmly pressed intothe tapped thread of the boss member, the outer edge or teeth 5 bitingin the materlal of the latter. Also, the coil end 2 will be widened inrelation to the remainder of the coil. Thus, simultaneously the coil endwill be secured in the boss, and the insertion of a stud used in a screwconnection of the boss facilitated.

In order to remove the tool, nut 21 hearing on the front surface 33 canbe turned to relieve the pressure of the wedge face 24 on the tongue,whereupon body 6 may be screwed out of the insert coil.

In order to secure the coil end still stronger in the boss, acylindrical punch may be combined with the parts heretofore describedand in a manner similar to that disclosed in U. S. Patent No. 2,325,508of July 27, 1943, to Haas and Hawkins. Whereas, however, according tothat patent suchcylindrical punch is'used to swage or stake the-entireannular ring zone of the boss member surface surrounding a tapped hole,in the instant of the present application it is preferable that thepunch acts only on that portion of the boss which is engaged by the end2 of the coil. For this purpose, a hollow cylindrical punch 35 isprovided which can be slid over body 8 with driver 2I therein as shownin Figs. 3 and 4. The punch has a front face 36 which is provided withaxially projecting teeth 31 arranged over an arc corresponding to thewidth of the tongue II. In order to insure the correct position of thethread in relation to the tongue, the punch is provided with a guidingpin 38 inwardly projecting and so arranged that it may engage theaforementioned groove 32 of the body 6. Inasmuch as tongue II 'willslightly project in a radial direction-from body Ii when the driver I9is applied, the punch is recessed at 39 in order to provide or sumcientspace for the tongue. If now, after body 8 with driver I9 has beenapplied to a coil and the edge of the coil end has been embedded in theboss member, driving of the punch against the latter will stake andcompress the boss material in the neighborhood of and particularly alsobetween the teeth 5 of the coil if such are provided. One of the teethof th punch, i. e. tooth 40, is preferably larger than the remainder ofthe teeth 31 and so located as to indent and compress the boss materialimmediately in front of the ultimate end of the inserted coil. Theembodiment illustrated and described hereinbefore is applicable to ahole in a boss or nut member which is open at both ends so as to permitthe tongue-provided end of body 6 to b passed through the hole and thatthe threading I2 may engage the inner threading constituted by aninsert. The modification of Fig. 7 illustrates part of a tool applicableto a coil in a blind hole. The illustration shows merely that portion ofthe tool which differs from the form shown in the preceding figures. Inthis modification the tongue-provided end 50 of the tubular body. 8' isprovided with two parallel slits I starting from the end face ii of thebody and extending towards the other end to points 9 so far remote fromthe face 5i that the resulting tongue I I is of sufficient resiliency.

Also starting from the face 5i the body portion 50 is provided with anexternal threading I2: similar to the threading I2 described inconnection with Figs. 3 to 6. One thread portion I3 with abutment I4 isprovided on the tongue in an arrangement similar to th equivalent partsI3 and I4, best shown in Fig. 6. The tongue portion between thethreading I3 and the face 5i 7 originally formed by the slitting of the.body may be cut off at 52. In all other respects the modi fled tool maybefsimilar to the first described embodiment, and it will now be clearthat the threaded end I2 may be screwed into an insert in a blind tappedhole as far as required, provided that the depth of the hole is notshorter than the length of the threading I2 and I3.

Figs. 8 and 9 illustrate the tongue-provided tubular body and wedgingrod of another modification. No punch is shown in connection with theseparts, but it will be clear that the punch 35 of the first describedembodiment may be used in combination with these modified parts. Thetubular body ill according to Figs. 8 and 9-comprises a substantiallycylindrical portion BI and a second portion 62 of a cross-section shapedas a segment of a ring. The size of the segment is larger than 180 andit may be formed by removing, e. g. in a cutting operation, the smallerand inserting the leaf spring end in the slot and bonding it at 61 tothe body 60 by welding, soldering or similar operation. The spring 65extends along the portion 62 and may bear on the faces 63 and 64. Theoutside of the other end of the spring is provided with a portion of athread 88 and abutment 69 similar to the thread It and abutment Mrespectively, first described. Instead of the abutment 69, one arrangedlike the abutment H4 of Fig. 6a may be provided. Although the body ofthe spring and the threaded portion may be made of one piece, it ispreferable to work the thread 68 into a little block 10 which is securedto the spring, e. g. by soldering or another suitable and conventionalmethod or means. The thread 68 constitutes the continuation of thethreading H on the portion 62 for the purpose mentioned hereinbefore.The spring 65 is provided on its inside with a wedge face projection 12which, similarly to the block 10, may be made as a separate piece andsecured to the spring. The projection 12 cooperates with the'wedging rod13 which is axially movable in body 60 and gu ded with pin 14 in theslot 15. The rod has a flat face I6 so as to clear the spring in a coilfor which the tool is destined, and fitting substantially the interiorof said coil, said tubular body further including a resilient tonguelikeportion in connection with and extending longitudinally from the one endof said first portion adjacent said second portion along at least partof said second portion, and transversely'so as tosubstantially cover thegap -between the ends of said segmental cross-section, said tonguehaving a radially oscillatable free end and ineluding, remote from itsconnected end, a portion of one external thread of a shape and pitchaccording to the inner threading constituted by said coil, and 'a wedgemember interiorly of said body and guided therein to engage and forcethe thread-provided tongue portion outward upon movement of said memberrelatively to said body.

2. A tool as claimed in claim 1, including an abutment for the coil endwhen engaging said thread portion of said tongue.

3. A tool for securing a wire coil insert with one of its ends in thetapped hole of a boss or nut member, comprising a tubular body includinga first portion of substantially circular crosssection, and a secondportion the cross-section of which constitutes a circular ring segmentof more than 180, said second portion being insertable in a coil forwhich th tool is destined and being provided with an external threadingof a diameter and pitch according to the inner threading constituted bysaid coil, said tubular body further including a resilient tongue-likeportion in connection with and extending longitudinally from the one endof said first portion adjacent said second portion along at least partof said second portion, and transversely soas to substantially cover thegap between the ends of 1 said segmental cross-section, said tonguehaving 65 when the rod is shifted in axial direction, and

has also, in continuation of said flat face an inclined face TI forengagement of the projection 12 of the spring. The rear end of the rodis shaped similarly to that of thesrod l9, i. e. it is provided with athreading 18 with adjustable nut 19 and stop collar 80, and with anextension 8!. The manner of application and the functions of the toolare the same as hereinbefore described with respect to the embodiment ofFigs. 3 to 6. The modification of Figs. 8 and 9 is preferable to theformer if a' s ofter spring action of the tongue is desired. Also, inthe case of the modification it is possible to repair the body if thethread 68 is worn, by exchanging the spring with block 10 or even merelythe latter, whereas no easy repair appears to be feasible if the tonguesof the other illustrated tools are destroyed for any reason.

It.will be apparent to those skilled in the art that many alterationsand modifications of the a radially oscillatable free end and beingprovided, in the zone of said external threading, with a portion of onethread in continuation of the one end of the threading of said secondportion, and a wedge member interiorly of said body and guided thereinto engage and force the threadprovided tongue portion outward uponmovement of said member relatively to said body.

4. A tool for securing a wire coil insert with an arc of one of its endconvolutions by radial pressure in a tapped hole, of a boss or nutmember, comprising a substantially tubular body provided with twolongitudinal slits so as to form therebetween a'resilient tongue of awidth substantially according to the length of the arc of the coilconvolution to be secured in the boss, said tongue having one end inconnection with said body and a radially oscillatable free other end andincluding a portion of one thread of a shape and pitch according to theinner threading constituted by said coil, said body being insertable insaid coil and fitting substantially the interior of said coil, and awedge member interiorly of said body and guided therein to engage andforce said tongue outward upon axial movement of said member in relationto said body.

5. A tool for securing a wire coil insert with one of its ends in atapped hole of a boss or nut member,comprising a substantially tubularbody provided with two substantially longitudinal slits starting at adistance from one end of the body and connected at their ends by atransverse slit, so as to form a resilient tongue extending in axialdirection of said body, a portion 01' the remainder of said bodyintermediate the ends of said slits including an external threadingaccording to the internal threading constituted by the wire coil insertfor which the tool is destined, said tongue including a portion or onethread 'in continuation of one or the end convolutions or said externalthreading to receive therein said end portion of said insert when the,tool is applied thereto, and a rod-like wedge interiorly of theremainder of said recessed body portion including an external threadingaccording to the internal threading constituted by said wire coil, saidbody being provided with two longitudinal slits spaced from each otheraccording to the width of said recess and extending from said recesstowards the other body end a length sumcient to form a resilient tonguebetween said slits, said tongue including a portion of one thread incontinuation of the adjacent end of said external threading, and a wedgemember interiorly of said body and guided therein to engage and forcesaid tongue outward upon axial movement of said member in relation tosaid body.

7. A tool for securing a wire coll insert with one of its ends in atapped hole of a boss or nut member, comprising a substantially tubularbody insertable in a coil for which the tool is destined and fittingsubstantially the interior of said coil,

said ,body being provided with two longitudinal slits so as to formtherebetween a resilient tongue, said tongue having one end connected tosaid body and a radially oscillatable free other end member in relationto said body, a removable substantially cylindrical punch of an innerdiameter similar to the outer diameter of said body, said punchincluding staking teeth projecting in axial direction from a portion ofits front face which is leading when the punch is applied to the bodyfrom the end opposite the tongue, said teethed portion being of a widthsimilar to that 01' said tongue, and means in connection with said bodyand said punch to guide the latter in axial direction with said teethedface portion in registry with said tongue.

8. vA tool as claimed in claim 7, said teeth including one tooth locatedlaterally of that end of the one thread of said tongue which is oppositethe end in continuation 01' said external threading of said remainderbody portion, said tooth being larger than the other teeth.

9. A tool for securing a wire coil insert with one of its ends ina'tapped hole of a boss or nut member, comprising a tubular bodyincluding a first portion of substantially circular cross-section, and asecond portion the cross-section of which constitutes a circular ringsegment of more than said second body portion being dnsertable in a coilfor which the tool is destined, and fitting substantially the interiorof saidcoil, a leaf spring having one end secured to said body close tothe end of the second body portion and a radially oscillatable freeother end, adjacent said first portion, said spring extendinglongitudlnally along at least part of said second portion andtransversely so as to substantially cover the gap between the ends ofsaid segmental cross- 01' said body and guided therein to engage and lforce the thread-provided spring portion outward upon movement of saidmember relatively to said coil, a wedge member interiorly of said bodyand guided therein to engag and force said said body.

HARKNESS w. CRAM. ERWIN ECKENER.

